Electrically operable motor vehicle door locks are distinguished by the fact that typically a locking element, as a component of a locking lever chain, is transferred to its “unlocked” or “locked” positions with the aid of a motor. That can occur in the sense of a central locking system, as has been known and is employed in practice. In this connection, examples of such devices are described in DE 25 40 675 A1, as well as to DE 29 11 630 C2, both of which describe the beginnings of such central locking systems.
For reasons of security, in many countries today motor vehicles are driven almost exclusively in the locked state. Thus, the subject motor vehicle often is centrally locked automatically as soon as travel is initiated. The occupants are thereby protected automatically, for example, from theft attacks at traffic lights. As soon as such a vehicle becomes involved in an accident, however, the danger exists that the main energy source—this is normally the storage battery (conventionally a battery) stored in the engine compartment or passenger compartment or in the back—is destroyed, or the supply cables break off.
For this reason, for emergency operation of the motor, as exemplified by DE 10 2005 026 377 A1, a capacitor has been proposed by which the motor is supplied briefly with electric current, so that the motor vehicle door lock can be opened mechanically. In this way, passengers can leave the wrecked vehicle on their own or can be rescued by rescue personnel without difficulty.
In the prior art, the objective is being able to activate the motor vehicle door lock again after an emergency operation. To this end, the known motor vehicle door lock has an actuator to disengage mechanical emergency connecting elements. The mechanical emergency connecting elements are engaged automatically when the power supply fails. In general, the actuator can be activated by hand.
The interaction between the known main energy source and the emergency energy source or the capacitor corresponding to DE 10 2005 026 377 A1 is not free of defects, however, because in the case of emergency operation emergency connecting elements are engaged. That can result in functional problems, and in addition drives up the requisite energy need, so that flawless operation cannot be guaranteed under all circumstances.